Wavelength modulated optical reflectivity spectra of CuAl_{1 −X}Ga_XSe₂crystals

Abstract

Exciton spectra of CuAl1 − XGaXSe2 solid solutions are investigated by wavelength modulated optical reflectivity at low temperatures (10 K). The energy position of n = 1 and 2 lines of the Γ4(A), Γ5(B) and Γ5(C) exciton series, as well as the Γ7(V1)–Γ6(C1), Γ6(V2)–Γ6(C1), Γ7(V3)–Γ6(C1) energy intervals, and the crystal field and spin–orbit splitting of the valence band are determined. The effective electron mass (mC1*) and hole masses (mV 1*, mV 2*, mV 3*) are estimated for CuAl1 − XGaXSe2 solid solutions as a function of the X value.

Influence of the annealing temperature on CuAlxGa1−xSe2 thin films obtained by selenization

“…References for CIAS thin films have been found with 0.51 eV ≤ b ≤ 1.06 eV 12, 26–29. No references have been found on CAGS thin films and the reported optical bowing parameters are related to single crystals and solid solutions with values 0.22 eV ≤ b ≤ 0.32 eV 30–32. In mixed‐cation alloys of the chalcopyrite system (Cu M Se 2 , M = Al, Ga, In) most of the level repulsion takes place in the conduction band.…”